An acronym and euphemism for the phrase "Sorry For Raging". S4R is the superlative and supreme state of S4P, or "Sorry For Partying". An individual must first reach a universally recognized S4P status before any acclamation of S4R can be made.

Ashley: "Do you realize you are dancing on a bar chair wearing women's tights and a Santa Claus apron at the bar while your ass is hanging out?"